'per centage'means 'the equivalent of per one hundred' - so if 8 of your children like strawberry ice cream ,that is the equivalent of 8/31 x 100 = 25.8 children out of every 100 liking it - that helps some and drives others crazy - use or ignore as appropriate!
(it would be much easier if you only had 30 )

sorry - which would mean 25.8% liked it
if only one child liked it, that would be the equivalent of 1/31 x 100 = 3.2 children in a hundred ie each child is 3.2% of the whole class - i can do maths, but i can't edit posts